ZIKA Virus and Mosquito Management

ACCG

Rosmarie Kelly, PhD MPH

30 April 16

• Zika virus (ZIKV) is a flavivirus related to yellow fever, dengue, West Nile, and Japanese encephalitis viruses.

• Zika virus was first discovered in Africa in 1947 in the Zika forest of Uganda.

• The first human Zika virus case was identified in Nigeria, Africa in 1954; only ~14 cases of ZIKV were reported before 2007.

• From 1951 to 1981, testing showed evidence of human exposure to Zika virus in other African countries.

• Between 1969 and 1983, Zika virus spread into Asia.

• As the Zika virus spread into new territories, it has evolved into two distinct lineages known as the African lineage and the Asian lineage.

What is Zika Virus?

The Spread of Zika Virus• In 2007 Zika virus caused an outbreak of relatively mild disease on

Yap Island in the southwestern Pacific Ocean.

• From 2013 through 2014 there was large outbreak of Zika virus on the Islands of French Polynesia; this outbreak then spread to other island groups.

French Polynesian Outbreak Zika Symptoms

• Zika symptoms tend to last from 2 to 7 days and most patients feel better after this short period of illness.

• Overall, Zika appeared to be a mild and self limiting illness; there were very few hospitalizations among the estimated 28,000 patients with symptoms.

• Only 70 Zika patients were hospitalized with severe illness:

• 38 developed Guillain-Barre syndrome, a disorder in which a person’s immune system attacks their nervous system, leading to paralysis

• 32 had various other neurological symptoms

Zika Arrives in the Americas 2014 -2015

• In May of 2015, an outbreak of Zika virus was discovered in several northeastern states of Brazil; it spread to 18 different Brazilian states by December 2015.

• A retrospective analysis of positive dengue test samples found Zika positive results in samples as early as February of 2015, although there is speculation that the virus actually arrived in Brazil in 2014.

• An analysis of the virus showed that it was of the Asian Lineage.

• Both Ae. aegypti and Ae. albopictus are thought to be playing roles in the Brazilian outbreak.

2015: Brazil declares emergency after

2,400 babies are born with brain

damage, possibly due to mosquito-

borne virus

CDC: First Zika Virus Case in the US Confirmed in Texas traveler - January 2016

Zika Arrives in the Americas 2016By January 2016, it was estimated that more than a million people had been infected in Brazil, and Zika cases had been seen in most countries of South America, Central America, Mexico and in numerous Caribbean countries.

Zika Virus Reservoir* Hosts1. Reservoirs of Zika virus for mosquitoes are non-

human primates (apes/monkeys, etc.) and people.2. It is not yet known if other animals participate in the

transmission cycle.

*A reservoir host is an organism that harbors a disease agent and remains infected for extended periods of time. Reservoir hosts serve as a source of the disease agent to vectors, but usually are not adversely affected.

How is Zika Virus Transmitted?

Mosquito bites:

• Zika virus is transmitted to people primarily

through the bite of an infected Aedes species

mosquito (Ae. aegypti and Ae. albopictus).

• Mosquitoes become infected when they feed on

a person already infected with the virus. After ~

10 days, infected mosquitoes can spread the

virus to other people through bites.

How Else is Zika Virus Transmitted?

• From mother to

child

• Through sexual

contact

• Possibly through

blood transfusion

Mosquito Control

• Although the vector is different, the public health message for Zika virus isn’t much different than the public health message for WNV– The 5 D’s (Drain, Discard, Dress, DAY, DEET)

– Personal Protection• Wear repellent

• Stay inside when mosquitoes are bad

• Wear long sleeves/long pants when outside

Aedes spp

Aedes aegypti (yellow fever mosquito)

• Urban mosquito

• Daytime biting mosquito

• Associates closely with people

Ae albopictus(Asian tiger mosquito)

•Suburban mosquito

•Aggressive, daytime biting mosquito

• Associated with used automobile tires

Where is the Highest Risk?

• Aedes albopictus is found in every county in Georgia

• This is one of Georgia’s top pest species after the

saltmarsh mosquitoes

• Because it feeds on a variety of hosts, the greatest risk of

disease transmission occurs in urban and suburban areas

where humans are the most abundant host

• This just in: For the first time in the Western Hemisphere,

researchers have detected the Zika virus in Aedes

albopictus, the mosquito species known as the “Asian

tiger,” a finding that increases the number of U.S. states

potentially at risk for transmission of the disease.

(Washington Post, 29 April 16)

Source Reduction

Specific activities for source reduction for Aedes mosquito are:

• Removal, disposal, burying or burning of all unnecessary items that can collect and hold water.

• Keeping all other items that can hold water in sheltered areas protected from rainfall.

• Emptying containers at least once a week.

• Arranging clean up campaigns once or twice a year in order to collect and remove all unused containers in and around houses.

Use larvicides and adulticides appropriately where source reduction fails to control all the mosquitoes.

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DPH – EHS PlanThe prevention or reduction of transmission of dengue, Zika, and Chikungunya is dependent on the control of mosquito vectors and limiting person-mosquito contact.

• Functions of mosquito surveillance programs:• Determine presence or absence of Ae. aegypti and Ae.

albopictus 

• Identify what types of containers are producing the most mosquitoes

• Develop detailed maps to track larval sites if Ae. aegypti or Ae. albopictus are detected in an area

• Collect mosquito population data and identify geographic areas of high abundance (high-risk)

• Monitor effectiveness of vector control efforts

• Collect data on mosquito infection rates (viral testing)

• Work with other agencies and organizations to provide education to the public

Vector Surveillance CoordinatorThis position has primary responsibility to conduct and coordinate mosquito surveillance for arborviral diseases such as West Nile Virus, Eastern Equine Encephalitis, Lacrosse Encephalitis, Zika and other arboviral diseases in a multi-county region. Duties will include: • establishing surveillance locations

throughout the PH Districts, • setting up traps and collecting mosquitos, • mosquito identification, • community assessments, and • education programs. When necessary, this position will coordinate mosquito control activities with existing city/county/contracted mosquito control agencies and assist with localized control efforts. In addition, this position supports the EH Team by assisting with surveillance for other public health issues of concern, including agents of bioterrorism (BT), tickborne diseases, rabies, bedbugs, and participates in outbreak detection and emergency response activities.

How will these things get done?

TASKS Options

initial educational contact Epidemiology

door to door education Environmental Health

larvicide EH or contracted mosquito control

surveillance EH or contracted mosquito control

barrier spray EH or contracted mosquito control

coordination with local mosquito control Environmental Health

Message for the Public – Terminate the TigerPractice the 5 Ds

Discard - get rid of anything you don’t need that can hold water

• Cleanup containers around your house

• Cleanup containers in your neighborhood (Community clean up)

Drain - dump out containers after every rain

• Tip ‘n Toss containers after each rainfall

• Don’t put saucers under your outdoor plants

• Use larvicides where you can’t dump out water

DEET - wear repellent when outdoors

• Follow label directions

• Apply when outdoors

Dress - wear light-weight clothing, long sleeves and long pants

Daytime - be aware of mosquitoes that bite during the day

• Asian tiger mosquitoes bite during the day

• They also bite at dawn and dusk

• 14 domestic and international concourses

• Countries with ongoing Zika transmission

• EPA registered insect repellents with DEET sold on the concourse

• Wear long sleeves, pants

• Air conditioning or screened in locations

• Use a mosquito net

Zika Travel Campaign

Zika Community Campaign

ANY QUESTIONS?